medwireNews: The benefits of later-stage exercise programs after total knee replacement (TKR) are unclear, say researchers, who found a disconnect between patient-reported outcomes and performance-based tests.
Sara Piva (University of Pittsburgh, Pennsylvania, USA), and colleagues describe their findings as “intriguing.”
They say: “While patient-reported outcomes like the WOMAC-PF [Western Ontario and McMaster Universities Osteoarthritis Index–Physical Function] evaluate what individuals perceive they can do, performance-based tests evaluate what individuals can actually do.”
The discrepancies may be partially explained by “the potential for the WOMAC-PF to underrepresent high levels of functional performance expected by patients who are at a later stage of recovery after TKR,” the researchers remark.
The study randomly assigned 240 individuals (mean age 70 years, 62% female) who had undergone TKR 2 to 4 months before enrollment to receive clinic-based individualized physical therapy (n=96), community-based group exercise in supervised classes (n=96), or usual care (n=48), each for 3 months.
At the end of the intervention period, all three groups reported clinically important improvements in the WOMAC-PF measure, which was the primary study outcome, with no significant differences between them. Improvements ranged from 10.8 points with physical therapy to 8.2 points with community exercise and 8.3 points with no intervention, from baseline values of 20.9, 20.4, and 20.2, respectively.
By contrast, the secondary outcome, which combined six performance tests (6-minute walk distance, 40-m gait speed, stair ascend/descend test, single-leg stance balance, chair rise, and floor sitting and rising) into a composite score, showed a significantly greater improvement in the physical therapy group compared with both the community and control groups at 3 months.
In addition, the response rate, defined as more than 20% improvement in both the WOMAC-PF and at least three of the six performance tests, was significantly higher in the physical therapy group compared with the community and control groups, at 32.6% versus 14.9% and 13.6%, respectively.
Writing in JAMA Network Open, Piva and co-authors note that although the differences between the arms based on the secondary outcomes favored physical therapy, they “were modest and require confirmation.”
They add: “It is possible that later-stage exercise may be too late after surgery to promote relevant benefits.”
“Perhaps a better model of later-stage exercise delivery (not tested in this study) would be a 2-stage approach. Individualized physical therapy could be delivered first to address the persistent functional limitations of selected patients, followed by long-term group exercise delivered in a community setting to promote sustained benefit,” the researchers suggest.
However, they also note that “this model needs exploration in future trials with longer-term follow-ups.”
By Laura Cowen
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